HP 10BASE-T Reference guide

HP AdvanceStack Switching Hubs

Reference Guide

Hewlett-Packard Company

8000 Foothills Boulevard, m/s 5551

Roseville, California 95747-5551

http://www.hp.com/go/network_city

This document contains information which is protected by

copyright. Reproduction, adaptation, or translation without

prior permission is prohibited, except as allowed under the

copyright laws.

Publication Number

5964-4662

Edition 1

August 1996

Applicable Product

HP J3200A Switching Hub-12R

HP J3202A Switching Hub-24R

HP J3204A Switching Hub-24T

HP J3210A Management Module

HP J3212A Switch Module

Disclaimer

The information contained in this document is subject to

change without notice.

HEWLETT-PACKARD COMPANY MAKES NO WARANTY

OF ANY KIND WITH REGARD TO THIS MATERIAL,

INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

WARRANTIES OF MERCHANTABILITY AND FITNESS

FOR A PARTICULAR PURPOSE. Hewlett-Packard shall not

be liable for errors contained herein or for incidental or

consequential damages in connection with the furnishing,

performance, or use of this material.

Hewlett-Packard assumes no responsibility for the use or

reliability of its software on equipment that is not furnished

by Hewlett-Packard.

Warranty

A copy of the specific warranty terms applicable to your

Hewlett-Packard products and replacement parts can be

obtained from your HP Sales and Service Office or

authorized dealer.

Perforate

✂

HP Customer Support Services

How to get the latest software/agent firmware

The hub does not have updatable firmware. You can update the following modules:

HP Management Module firmware: j3210a.exe

HP Switch Module firmware: j3212a.exe

from the HP BBS, HP FTP Library Service, CompuServe, and the World Wide Web.

After you download the file, extract the file by typing:

filename

/x. For example,

j3210a.exe /x

HP BBS

Set your modem to no parity, eight bits, 1 stop bit, set speed up to 14400 bps, and with

your telecommunication program (e.g., Windows Terminal) dial (208) 344-1691 to get

the latest software for your HP networking product.

HP FTP Library Service

1. FTP to Internet IP Address — ftp ftp.hp.com.

2. Log in as anonymous and press [Return] at the password prompt.

3. Enter bin to set the transfer type.

4. Enter cd /pub/networking/software.

5. Enter get

filename

to transfer the file to your computer, then quit.

CompuServe

1. Login to CompuServe.

2. Go to the “hp” service.

3. Select “HP Systems, Disks, Tapes, etc.”

4. Select “Networking Products” library.

5. Download filename then quit.

World Wide Web

http://www.hp.com/go/network_city

Select the “Support” section.

From this web site you can also download information on the HP Switching Hubs and

HP AdvanceStack Assistant. If you have a growing network, download the Designing

HP AdvanceStack Workgroup Networks Guide or call 1-800-752-0900 to receive a copy

through mail.

(over for more services)

Obtain the latest console code (j3210a.exe) from

HP FTP Library: ftp ftp.hp.com

World Wide Web: http://www.hp.com/go/network_city

HP BBS: (208) 344-1691

(over)

Perforate

✂

HP FIRST Fax Retrieval Service

HP FIRST is an automated fax retrieval service that is available 24 hours a day, seven

days a week. HP FIRST provides information on the following topics:

■ Product information

■ Troubleshooting instructions

■ Technical reviews and articles

■ Configuration information

To access HP FIRST, dial one of the following phone numbers:

HP Network Phone-In Support (NPS)

In addition to the above services, the HP Network Phone-In Support (NPS) service

provides expert technical assistance for U.S.A. customers through an NPS contract or

at an hourly rate (1-800-790-5544) Monday through Friday, 5 am to 6 pm, Pacific Time.

You may also contact your HP Authorized Reseller or the nearest HP Sales and Support

Office to purchase an NPS contract.

Location Phone Number

U.S. and Canada Only Dial 1 (800) 333-1917 with your fax machine or touch-tone phone

and press 1.

Outside the U.S. and Canada Dial 1 (208) 344-4809 from your fax machine and press 9.To

receive a list of currently available documents, enter document

number 19941. The information you requested will be sent to you

by return fax.

CompuServe: Go the “hp” service.

Select HP systems, etc.

Select Networking Products.

Download the file.

Network Phone-In

Support (hourly):

1-800-790-5544

iii

Contents

1 Switching Hub Features

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Front of the Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

LED Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Hub Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Coexistence of Switching Hubs with Other Ethernet Hubs . . . . . . . . 1-4

Resetting the Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Extender Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Stack Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

Back of the Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

Power Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

Redundant Power Supply (RPS) Connector . . . . . . . . . . . . . . . . . . . . . 1-7

Expansion Slot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

How the Hub Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

Collision Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

Auto-Partitioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Link Beat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

2 Optimizing Your Network

Automatically Segmenting Your Network . . . . . . . . . . . . . . . . . . . . . . . 2-2

Reasons for Using an Internal vs. External Switch . . . . . . . . . . . . . . . . 2-2

HP Internal Switch Module Features . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Managing Your Network with the Management Module . . . . . . . . . . 2-4

3 Troubleshooting

Solutions to Common Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

LED Error Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

iv

Diagnostic Tests

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Testing the Hub or Stack of Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Testing Twisted-Pair Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

HP Customer Support Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

A Cables and Connectors

Recommended Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Twisted-Pair Cable/Connector

Pin-Outs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

Twisted-Pair Cable for Hub-to-Computer

Network Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

Twisted-Pair Cable Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . A-3

Twisted-Pair Straight-Through Cable . . . . . . . . . . . . . . . . . . . . . . A-3

B Specifications

C Safety and Regulatory Statements

Mounting Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

Power Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2

Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3

Index

1-1

1

Switching Hub Features

Introduction

With the Switching Hubs, you can connect computers, servers, and printers

together in an Ethernet network for sharing files. These hubs can coexist with

any IEEE 802.3 Type 10Base-T standard hub including HP AdvanceStack and

HP EtherTwist products. The three Switching Hub models are:

Each hub has four segments or collision domains. By default, all users are put

on segment 1. If you add a Management Module, you can distribute the ports

over the four segments.

This chapter describes the features of the Switching Hubs.

HP J3202A Switching Hub-24R

HP J3204A Switching Hub-24T

HP J3200A Switching Hub-12R

1-2

Switching Hub Features

Front of the Hub

Switching Hub Features

Front of the Hub

LED Operation

LED State Meaning

Power (green) Off The hub is not receiving power.

On The hub is receiving power.

Fault On The hub has failed its self-test after being powered on

or reset.

Flashing

Slowly*

A port has partitioned or a connected RPS has a failure.

The corresponding LED will also flash.

Off The normal state. Indicates that there are no fault

conditions on the hub.

Security

(only

available if a

Management

Module is installed

in the stack)

Flashing

Rapidly**

A security violation has occurred on a port. The

corresponding port is flashing at the same time for the

port violation. Otherwise an SNMP intrusion has

occurred on the Management Module. This intrusion

may have occurred before the last hub reset.

To view security violations or turn off flashing LEDs, use

the ASCII console or HP AdvanceStack Assistant as

described in the

HP Management Module Installation

and Reference Guide.

Off No security violation detected (the normal state).

RPS Off This hub is not receiving power from the HP J2962A

Redundant Power Supply (RPS).

On This hub is receiving power from the connected RPS.

Flashing

Slowly*

An error has occurred on the RPS connected to the hub.

See the documentation provided with the RPS for

troubleshooting.

Expansion Slot

Module label

The LED behavior depends on the module inserted into

the Expansion Slot. See the module manual for a

description of these LEDs.

1-3

Switching Hub Features

Front of the Hub

Switching Hub Features

LAN Segment 1-4

Act (green)

Col (orange)

Flickering

Shows the activity and collision status for each

segment. Segment 2-4 LEDs flicker if you have moved

ports to these segments using an optional Management

Module and/or Switch Module.

Collision LED: If collisions are infrequent (which is

normal) the light may be imperceptible. In a network

with heavy traffic, the Col LED will glow and flicker

dimly, indicating collisions are occurring. If it appears

on continuously (with no flicker), it is a possible

indicator of a network fault.

Activity LED: ON while a packet is being transmitted.

Normally, the LED appears to flicker. In heavy traffic, it

may be on all the time.

Xcvr Off There is no transceiver installed or the port has been

disabled through the ASCII console or HP

AdvanceStack Assistant. (A Management Module is in

this stack of hubs.)

On The Transceiver module is enabled and not partitioned.

Flashing

Slowly*

The port has been partitioned. The Fault LED will also

be flashing at the same rate. See “Partitioning” later in

this chapter.

Flashing

Rapidly**

The port has experienced a security violation. The

Security LED will also be flashing at the same rate.

To turn off flashing LEDs, select Security from the ASCII

console or HP AdvanceStack Assistant.

Twisted-Pair Ports Off The port is not receiving the link beat signal from the

attached node or the port is disabled.

On The port is enabled and link beat is detected from the

attached node.

Flashing

Slowly*

The port has been partitioned. The Fault LED will also

be flashing at the same rate. See “Partitioning” later in

this chapter.

Flashing

Rapidly**

The port has experienced a security violation. The

Security LED will also be flashing at the same rate.

To

turn off flashing LEDs, select Security from the ASCII

console or HP AdvanceStack Assistant.

* The slow flash rate is approximately once every 1.5 seconds.

** The rapid flash rate is approximately 3 times each second. This condition can exist only

if a Management Module is installed in the hub.

LED State Meaning

1-4

Switching Hub Features

Front of the Hub

Switching Hub Features

Hub Identification

Below the AUI/Xcvr (Transceiver) port is a label with the Hub Identification

number and serial number. The Hub Identification number is displayed in the

ASCII console and HP AdvanceStack Assistant to identify the hub in the stack.

The format is:

123-1234567

The Hub Identification number is not the MAC address. The Switching Hub

does not have a MAC address because it cannot be managed without a

Management Module. See the Management Module manual for information on

the MAC addresses for a stack.

Coexistence of Switching Hubs with Other Ethernet

Hubs

If you have an existing stack of hubs, connect a network cable from one stack

to the other as shown on the topology card included with the hubs (5182-9815).

Resetting the Hubs

You can reset the hub by unplugging and plugging back in the power cord;

each hub does not have a reset button. By reinserting the power cord, the hub

performs the power-on self-test. No configuration is changed.

1-5

Switching Hub Features

Front of the Hub

Switching Hub Features

Extender Cables

The Extender Cable is for communication between users on the same segment

across the stack. Use the Extender Cable to connect up to 8 hubs together to

make one segment.

As one segment, the connected stack of hubs are considered to be one repeater

hop. On initial bootup, all users are placed on segment 1 if no Management

Module is present.

Without the Extender Cable, each Switching Hub has its own collision domain.

If you need to manage your stack of hubs, or segment your hubs into different

collision domains, see chapter 2, “Optimizing Your Network”.

Stacked hubs can be close together or physically distributed. Each Extender

Cable included with a hub is 31.8 cm (12.5 inches). For longer distances, order

the Long Extender Cable (71 cm, 28 inch), part number 5182-9869, by calling

1-800-538-8787.

Extender Cable

1

2

3

4

5

6

7

8

One repeater hop

1-6

Switching Hub Features

Front of the Hub

Switching Hub Features

Each stack can have a maximum of two 71 cm (28-inch) cables. Using two 28-

inch cables and five 12.5-inch cables, the maximum distance is 2.9 meters (9.9

feet). The following illustration shows a stack of hubs and Long Extender

Cable connections that go over an HP Switch 2000 and to a hub in another

stack:.

Stack Order

The stack order is determined by which hub has only an Extender Cable

connected to the OUT port. Notice that all illustrations in this manual show

the top hub with the cable in the OUT port only. By following this topology,

the ASCII console and HP AdvanceStack will accurately report which hub is

at the top of the stack and number the hubs beneath it in increasing order.

Extender cable

1

2

3

4

5

Long Extender cable

Switch 2000

6

7

8

Out

1-7

Switching Hub Features

Back of the Hubs

Switching Hub Features

Back of the Hubs

Power Connector

The hub does not have a power switch; it is powered on when the power cord

is plugged into the power connector. The Switching Hubs automatically

adjusts to any voltage between 100-127 and 200-240 volts and either 50 or 60

Hz. There are no voltage range settings required. If a hub were to fail, all of

the other hubs connected to the Extender Cable remain operating because

they have separate power cords.

Redundant Power Supply (RPS) Connector

The RPS connector allows you to connect this hub to the HP J2962A Redun-

dant Power Supply. A single RPS shares the load with up to 4 hubs. The RPS

has several power supplies to keep the hub up and running.

Expansion Slot

The Expansion Slot is used to add connectivity/functionality through modules

such as the HP J3212A AdvanceStack 10BT Switch Module to the stack. Other

modules may be available. Contact your HP-authorized dealer or reseller for

more information.

Expansion slot modules have a color on them that match a color bar on the

hub. Before inserting a module, verify that the color matches. The Switch

Module features are described in chapter 2, “Optimizing Your Network”.

power receptacle

on the back of the hub

Expansion Slot

1-8

Switching Hub Features

How the Hub Works

Switching Hub Features

How the Hub Works

The HP AdvanceStack Switching Hubs are multiport repeaters that conform

to the IEEE 802.3 repeater specification. Data signals coming into the hub

from any of its ports are automatically regenerated and transmitted to all the

other network ports on the same segment in the hub stack. The hub regener-

ates the data without interpreting the contents, so it can be used in either IEEE

802.3 or Ethernet networks and with any upper-level protocol.

The following illustration shows communication when there is no Manage-

ment Module in the stack.

If users are distributed on the different segments via a Management Module,

then data received on a segment is only transferred out the same segment.

Collision Detection

The hub performs collision detection. A collision occurs when two nodes try

to transmit at the same time. When the hub detects this, it stops repeating the

colliding transmissions and starts transmitting a jamming signal. The jamming

signal tells the transmitting nodes that a collision has occurred. The colliding

nodes then stop transmitting for a random amount of time before attempting

to retransmit the data. Once the collision condition is removed, the hub stops

transmitting the jamming signal and normal operation is resumed.

Data comes in Port 11

Example: John is connected to port 11 and transmits data out of his PC. Data is

repeated out of all ports in this stack because they are all on segment 1.

Hub A

Hub B

1-9

Switching Hub Features

How the Hub Works

Switching Hub Features

If the Col LED is on most of the time because of high traffic levels, you can

optimize your network by separating nodes onto different segments. Each

segment is a collision domain. By adding the optional Management Module to

your stack of hubs, you can use management software to specify which

segment each node will be placed on.

Auto-Partitioning

The hub will automatically partition (temporarily disable) a network port for

the following reasons:

■ a collision condition exists for an excessive duration (between 1024

and 2048 bit times)

■ a collision occurs during each of 32 consecutive attempts to transmit

■ Installed optional transceiver has SQE test enabled instead of

disabled

The hub monitors the partitioned port and automatically re-enables the port

when a minimum length packet can be successfully transmitted or received

without a collision occurring.

Excessive collisions may be caused by faulty wiring. If a port’s transmit

(Tx +/-) wires have been shorted to the receive (Rx +/-) wires of any port, a

collision will be detected when that port attempts to transmit. If a port’s

receive (Rx +/-) wires are not connected properly, collisions will occur

because the hub cannot detect the presence of network traffic on that port

and may thus transmit at inappropriate times.

A port may occasionally also become partitioned when network traffic is

extremely heavy causing an abnormally high collision rate. If collisions are

high, distribute your users onto two, three or four segments using the optional

Management Module.

1-10

Switching Hub Features

How the Hub Works

Switching Hub Features

Link Beat

Type 10Base-T devices use a signal called link beat (also called link test pulse).

This signal informs the hub of the presence of a device connected to it over

twisted-pair cable and of the integrity of the twisted-pair link between them.

The hub will not transmit packets out of twisted-pair ports that do not sense

the link beat signal. Link beat is reflected in the port LEDs; the LED will be on:

Link beat status shown in Port LEDs

2-1

2

Optimizing Your Network

If your Col(ision) and/or Act(ivity) LEDs are mostly on rather than flickering,

you can optimize your network by adding these optional modules:

■ Management Module and Switch Module to automatically dis-

tribute users onto the different segments

■ Management Module only to manually distribute users over your

network onto the different segments

Because the Switch Module needs a Management Module in the stack, you can

configure, troubleshoot, and monitor your network with either setup.

Note You can also add additional LAN adapters to your server or an external switch

to communicate with the Switching Hubs. See those products documentation

for more information.

This chapter describes the following topics:

■ automatically segmenting your network using an internal or external

switch

■ features of the internal Switch Module

■ features of the Management Module

2-2

Optimizing Your Network

Automatically Segmenting Your Network

Optimizing Your Network

Automatically Segmenting Your

Network

If you have multiple servers connected to your hubs, you can improve access

time to the servers by adding a switch. You can add an internal switch module

or external switch.

Reasons for Using an Internal vs. External Switch

Some of the main differences between an internal and external switch are

listed in below.

For information on HP external switches, contact your HP authorized dealer

or reseller. For more information on an external switch, contact the manufac-

turer of the switch.

Reasons to use an

Internal Switch Module

Reasons to Use an

External Switch

Need an inexpensive performance

boost within a 10Base-T framework

Need higher performance boost (fat pipe, switched

10Base-T to desktop)

Need just basic management plus

auto-configuration and load balancing

features

Require full management:

spanning tree

dropped packet detection

No pre-configured bridging or switch-

ing

Pre-configured bridging or switching on network

Half duplex to servers is adequate Need full duplex speed to servers

2-3

Optimizing Your Network

Automatically Segmenting Your Network

Optimizing Your Network

HP Internal Switch Module Features

The plug-and-play HP J3212A AdvanceStack 10BT Switch Module inserts into

the Expansion Slot of your Switch Hub.

The features of the Switch Module are:

■ Automatic Port Switching. If you have not changed the port con-

figuration in the ASCII console or HP AdvanceStack Assistant (setting

up security, disabling ports), the Management Module will move the

ports onto the four different segments for you automatically on power

up.

■ Load Balancing. In both the ASCII console and HP AdvanceStack

Assistant, you can select Load Balancing and the software will exam-

ine your network traffic, and redistribute the ports to balance the

network load.

■ Connect the Segments Together. Users on one segment can com-

municate with the users on another segment through the Switch

Module backplane.

The Switch Module has four external ports. The Xcvr (Transceiver) port

supports twisted-pair, thin coax, and fiber media for external connections to

servers at

10 Mbit/s. Internally, the Switch Module connects to the four segments in the

hub stack.

Because the Switch Module requires a Management Module in a managed

stack, you get all of the features of the Management Module described on the

next page for your hub stack.

Xcvr

Fault

Requires HP J3210A Management Module

2-4

Optimizing Your Network

Managing Your Network with the Management Module

Optimizing Your Network

Managing Your Network with the

Management Module

By adding the optional HP J3210A Management Pack to any hub in your stack,

you can configure, diagnose, and troubleshoot your stack of hubs.

The features of this module are:

■ Port Switching. The ability to distribute any stack ports onto 4

available segments. By distributing ports onto different collision

domains, the number of collisions are reduced and bandwidth in-

creases for each user.

■ Network Management through Two Included Software Inter-

faces. Segment, diagnose, configure, and manage your stack of hubs

through either the ASCII console (through a serial cable or by using

Telnet) or through the graphical software package, HP AdvanceStack

Assistant. Using either interface from a network management station

that supports Management over IP (using the configured IP address)

or Novell NetWare (IPX), you can remotely manage the stack of hubs.

The Management Module has SNMP, RMON, and HP EASE (Embed-

ded Advanced Sampling Environment).

■ Segment Display. The Management Module has a Segment Display

button. By pressing the Segment Display button one time for each

segment, all Port LEDs in the entire stack will reflect which segment

each port is on. After 60 seconds, the Port LEDs revert to displaying

their connection status information rather than segment information.

■ Security Multiple levels of security and network management autho-

rization for every port in the stack. The console can also be configured

to have a password before the user logs in.

■ Redundant backup link to another device to enhance network fault

tolerance for every port in the stack.

■ Redundant Management Modules. If you insert two Management

Modules into a stack, the second module will take over if the first one

fails to give you uninterrupted management.

Active

Base MAC Address

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